JP2003287868A - Opc mask and laser repair device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser mask repair device which uses an optical proximity correction (OPC) slit and performs a correction working having a resolving power of the resolution of a working optical system or more. <P>SOLUTION: Instead of a variable XY slit mechanism used in the conventional mask repair device, a pattern of Cr film attached to a glass substrate similar to a photomask is made to be the mask and the mask formed with an OPC pattern such as a serif on the pattern is used and, thereby, the working having about 1/2 R as the ratio with the conventional one is enabled. Further, both of the conventional variable XY slit mechanism and the slit mechanism by means of the OPC mask are mounted, the both are used while being changed selectively and, thereby, the correspondence to various sizes and defects of shape are enabled. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an OPC mask for repairing defects in a photomask used in a pattern exposure process of a semiconductor manufacturing apparatus or a liquid crystal manufacturing apparatus, and a laser repair apparatus.

[0002]

2. Description of the Related Art A laser mask repair apparatus is an apparatus for repairing defects generated in a photomask used when a circuit pattern is printed on a silicon wafer, which is an essential part of semiconductor manufacturing, by using laser light. Japanese Patent Application No. Sho 55-0679
No. 30 (filing date May 23, 1980) filed the first patent application. The disclosed device has a configuration in which a rectangular shape freely determined by a variable rectangular slit mechanism is reduced and imaged on a photomask by an imaging lens to correct a defective portion. The minimum size (resolution limit) R that can be corrected is expressed by Rayleigh's equation R = k ₁ λ / NA (1) where the wavelength λ of the laser light and the numerical aperture of the objective lens are NA. Here, k ₁ is a coefficient determined by the optical system and is usually about 0.5. From the equation (1), when R is made small, either the wavelength λ is made small, the NA is made large, or both are realized. Where λ is the wavelength of the third harmonic of the Nd: YLF laser, 0.351 μm, or the wavelength of the fourth harmonic, 0.26.
The value is determined by the laser used, such as 3 μm. Possibly the wavelength of the fifth harmonic is 0.2
There is a possibility that it can be used up to 11 μm, but practically it is difficult. This wavelength is in the wavelength region close to the vacuum ultraviolet region, and it is difficult to design and manufacture a high-performance objective lens with small aberration in this region. Further, since the chromatic aberration due to the difference in wavelength from the ultraviolet lamp that can be used as the illumination light is corrected, the objective lens is forced to be designed more severely. As a result, even if it is forcibly designed and manufactured, an optical system having a higher resolution can be obtained by using an objective lens having high performance at the third and fourth harmonics.

As for the NA, it becomes more difficult to design a lens having a higher NA. In addition, when designing with wavelengths in the ultraviolet region such as the third and fourth harmonics, there is a limit to the lens material that can be used, so considering a high performance lens, NA = 0.80 to 0.85. The degree is the limit.
As described above, in the formula (1), there is a limit to the design of decreasing the wavelength λ or increasing the NA. Currently, when designing with λ = 0.351 μm, the coefficient k ₁ is To realize an optical system that can achieve about 0.5, N
This is near the limit of the NA value that can be used by the objective lens of A = 0.85.

If the depth of focus (DOF) and the work distance (WD) of the lens are made extremely small (short), NA =
0.90 to 0.95 will be possible, but if WD is short,
There is also a high possibility of contacting an expensive photomask during work and damaging the mask. Furthermore, if the DOF becomes very short, the performance of autofocus (AF) provided in the objective lens is directly linked to the processing, so that the processing is generally unstable and the apparatus becomes very difficult to use. As a result, the resolution when the wavelength of 0.351 μm is used is R = 0.25 μm in the equation (1), and even if the actual repair processing is performed, the radius of the corner is 0.25 μm.
The current situation is that a curvature of about m is attached. In other words, even if the objective lens having the current highest resolution is used, if the slit shape is set to 0.5 μm square and processed, as shown in FIG.
Only a circle of 5 μm.

[0005]

The above-mentioned current limit of resolution is not expected to be greatly improved unless the problems of trade-off of shorter laser wavelength and higher NA of objective lens are solved. Have difficulty. For example, unless there is an epoch-making optical material with a high refractive index, which has a quality comparable to that of synthetic quartz in the ultraviolet region, great progress is unlikely. Therefore, in the present invention, the objective lens is used as it is,
The object is to realize processing with further improved resolution.

[0006]

According to a first aspect of the present invention, there is provided a laser repair apparatus, wherein a laser and a slit mechanism capable of irradiating the laser emitted light and varying a slit width in two dimensions. Irradiating the laser emission light, the optical proximity effect correction (O
PC), a glass mask having at least one or more patterns in consideration, a transmission image of the slit mechanism, and an image forming optical system for reducing and forming the transmission image of the glass mask on the same plane. The object to be processed arranged on the surface is processed by the imaged light spot.
The laser repair apparatus according to the invention according to claim 2 of the present invention selects either the slit mechanism of the slit width variable or the glass mask for the laser emission light according to the invention according to claim 1. It is characterized in that it has a mechanism for switching an optical path for irradiating the light. Further, in the laser repair apparatus according to the invention of claim 3 of the present invention, the glass mask according to the invention of claim 1 can select a pattern for irradiating the laser beam from the plurality of OPC patterns. As described above, a mechanism for moving the optical axis in a direction perpendicular to the optical axis direction is provided. According to a fourth aspect of the present invention, there is provided a laser repairing apparatus, wherein the OPC glass mask according to the first aspect of the present invention is a binary mask including a light transmitting region and a light shielding region, or a phase shift mask. It is characterized by being manufactured in. In the laser repair apparatus according to the invention of claim 5 of the present invention, the phase shift mask according to the invention of claim 4 is one of a halftone type, a Levenson type, and a self-aligned type. Characterize. Further, in the laser repair apparatus according to the invention according to claim 6 of the present invention, the laser beam for irradiating the slit mechanism and the glass mask according to the invention according to claim 1 or 2 has different pulse characteristics. Characterize. The laser repair apparatus according to the invention according to claim 7 of the present invention is the laser repair apparatus according to claim 6 of the invention.
Laser light irradiating the PC mask has a pulse width of 100 fs
It is characterized in that it is a pulse train having a pulse width of 10 ps to 300 ps, and the laser light with which the slit mechanism is irradiated has a pulse width of 10 ps to 500 ps. Further, in the laser repair apparatus according to the invention of claim 8 of the present invention, the laser light having different pulse characteristics described in the invention of claim 6 or 7 is laser light emitted from two different lasers. It is characterized by Further, the laser repair apparatus according to the invention according to claim 9 of the present invention is used in the glass mask according to the invention according to claims 1 to 8.
The PC pattern is a serif type or a hammerhead type. According to a tenth aspect of the present invention, there is provided a laser repair apparatus, wherein the shifter material of the phase shift mask according to the fourth aspect of the invention is MoSi, Si, ZrSi, Cr or TiS.
It is characterized in that any one of i-based materials and materials based on these materials is used. In addition, claim 11 of the present invention
A laser repair apparatus according to the invention according to claim 1, wherein a laser, an optical branching unit that splits the laser light into two, and generates a first branched light and a second branched light, and irradiates the first branched light,
A first glass mask having only a square pattern portion of an OPC pattern; a second glass mask which is irradiated with the second branched light and has only a serif portion of the OPC pattern located at a corner of the square pattern; An object to be processed which is provided with an optical combining means for synthesizing transmission images of two glass masks, and an image forming optical system for reducing and forming the synthesized transmission images on the same plane. Is processed by the light spots which are combined and imaged in an OPC pattern. In the laser repair apparatus according to the invention of claim 12 of the present invention, the first and second glass masks according to the invention of claim 11 have a plurality of patterns having different shapes or sizes. However, the pattern for irradiating the laser beam can be selected from the plurality of patterns. Further, in the laser repair apparatus according to the invention according to claim 13 of the present invention, when the length of one side of the first square pattern provided in the first glass mask according to the invention according to claim 11 is 100. The side of the second square of the serif portion of the second glass mask is 20 to 40, and the length of the overlapping portion of the first square and the second square is 0 to 20.
It is characterized in that a square is processed by the light spot imaged on the OPC pattern having a ratio of. According to a fourteenth aspect of the present invention, there is provided a laser repair apparatus, wherein the optical path is switched between the optical path switching mechanism and the slit width variable slit mechanism described in the first invention, and the optical path is switched. A beam expander capable of independently adjusting the beam divergence angle is provided in the optical path between the mechanism and the glass mask. Also,
According to a fifteenth aspect of the present invention, in the laser repair apparatus, the independent beam expander according to the fifteenth aspect of the invention is such that the processed shape when using an OPC mask is the best. It is characterized in that a magnification rate different from that of the variable XY slit mechanism can be selected. According to a sixteenth aspect of the present invention, there is provided a laser repair apparatus, wherein the glass mask according to the first to fourteenth aspects of the invention has an optical axis direction when the reduction image forming magnification is 1 / M. And a fine movement stage mechanism having a resolution of 10 M nanometers or less in a direction perpendicular to the optical axis. According to a seventeenth aspect of the present invention, there is provided a laser repair apparatus, which moves an image forming position by moving the glass mask according to the sixteenth aspect of the invention in an axial direction perpendicular to an optical axis direction. The feature is that a minute amount can be shifted. The laser repair device according to the invention of claim 18 of the present invention is the laser repair device according to the invention of claim 16, further comprising means for measuring the imaged light spot, The fine movement stage mechanism constitutes a feedback servo system with the imaging light spot measuring means, and the position of the imaging spot in the optical axis direction is automatically controlled by the servo system. Further, claim 1 of the present invention
The laser repair apparatus according to the invention of 9 relates to a focus position when processing with the variable XY slit mechanism according to the invention of claim 16 and a focus position when processing using the OPC glass mask. It is characterized by matching. An OPC mask according to a twentieth aspect of the present invention is an OPC mask including a rectangular pattern and a pattern having serifs at corners of the rectangular pattern in consideration of optical proximity correction. The pattern is composed of two masks, and the pattern width of the square can be varied in one axis direction by sliding the two masks in one axis direction along the main surface. A laser repair apparatus according to a twenty-first aspect of the present invention irradiates a laser and the laser emission light, and X
The first OPC mask according to the present invention according to claim 20, wherein the rectangular pattern width can be varied in the axial direction, and the laser emission light is irradiated to vary the rectangular pattern width in the Y-axis direction. The second OPC mask according to the invention according to claim 20 and the first OP
A transmission image of the C mask and an image forming optical system for forming a reduced image of the transmission image of the second OPC mask on the same plane are provided, and the object to be processed arranged on the image forming surface is imaged. It is characterized in that it is processed by a light spot. According to a twenty-second aspect of the present invention, there is provided a laser repair apparatus, wherein the laser emission light according to the twenty-first aspect of the invention is generated by using either the first OPC mask or the second OPC mask. It is characterized by having a mechanism for switching an optical path for selective irradiation. A laser repair apparatus according to a twenty-third aspect of the present invention is a laser, an optical branching unit that splits the laser beam into two beams, and generates a first branched beam and a second branched beam, and Irradiate the branched light of 1, XY2
21. The first OPC mask according to claim 20, wherein the square pattern width can be varied in the X-axis direction of the axes, and the square pattern width is irradiated in the Y-axis direction by irradiating the second branched light. 21. The second OPC mask according to claim 20, which is variable, an optical merging unit that combines the transmission images of the two glass masks, and the combined transmission images are reduced and imaged on the same plane. An image forming optical system is provided, and the object to be processed disposed on the image forming surface is combined and processed by the light spot imaged on the OPC pattern. A laser repairing device according to a twenty-fourth aspect of the present invention can irradiate a laser and the laser emission light to change the rectangular pattern width in the X-axis direction of the XY2 axes. The OP according to the invention according to claim 20, having a mechanism for rotating 90 degrees in the Y-axis direction.
A C mask and an image forming optical system for forming a reduced image of the transmission image of the OPC mask, and an object to be processed arranged on the image forming surface is processed by the imaged light spot. To do.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In order to achieve the purpose of realizing processing with further improved resolution, the objective lens is used as it is, and in the present invention, optical proximity correction (OP) is used.
C: Optical Proximity Corre
It is considered that processing that exceeds the resolution limit is enabled by using the action. The optical proximity effect refers to, for example, a KrF excimer laser exposure apparatus having a wavelength of 0.248 μm and having an optical density of 0.
When a fine pattern having an exposure wavelength of 20 μm or less is to be formed, if there is a difference in the density of the surrounding patterns, the degree of diffraction or interference slightly changes, resulting in a dimensional difference in the formed pattern. Is. More specifically, when the distance between the adjacent patterns in the mask pattern is wide to some extent, the exposure image can be formed in a size according to the set value of the mask pattern.
If the distance between the mask pattern and the adjacent pattern is narrower than a certain distance, a dimensional error occurs in the exposure pattern, which increases the size. Therefore, in order to cope with this phenomenon, a simulation is performed in advance to give a correction amount to the original data of the pattern so that the pattern after exposure does not change. This is the optical proximity correction (OP
It is said to be C). Semiducuc
tor FPD World 2000.7, p209
As shown in Fig. 1, typical OPC patterns called serif type and hammerhead type (Fig. 1
7B) is applied to the slit shape of the mask repair, the radius of curvature of the rounded corner portion at the diffraction limit can be reduced as shown in FIG. 16B.

In the present invention, an experiment was conducted to confirm the effect of using an OPC mask by using the configuration of the standard optical system for laser repair shown in FIG. The experimental system irradiates the variable XY slit 20 with the irradiation light 7, guides the transmission image of the slit surface 10 to the objective lens 5 by the relay lens 2, the two folding mirrors 3 and 4 and slits the image plane 6 with a slit. This is a configuration in which a transmission image is formed into a reduced image. × 1/200 reduction imaging optical system, 100μ
An image of an m-square slit shape is formed into a 0.5 μm square. The NA of the objective lens 5 is 0.85, the laser light used has a wavelength of 351 nm and a pulse width of 250 ps. Results of laser processing when using a normal slit mechanism and OPC
A comparison was made with the processed shape when the glass mask was used, and the improvement state when the OPC glass mask was used was investigated. In the evaluation using the OPC mask, the parameters shown in FIG. 19 were defined. In the figure, a is fixed to 100 μm and b is 0, 10, 20, 30, 4
A mask pattern in which 0 μm and c were changed to 0, 10 and 20 μm was prepared and evaluated using this. As a result, b =
A remarkable improvement effect was obtained when 30 to 40 μm and c = 0 μm. The larger the c value, the less the effect of corner resolution as shown in FIG. 16B becomes, and this effect was not remarkable unless the b-c value was about 30 μm. As a further finding, when the laser pulse width is evaluated at 30 ps, the pulse width is reduced to about 1/10 and the thermal diffusion length is shortened. Therefore, the effect of OPC can be seen even if the bc value is small. There was found.

Next, an embodiment of a laser mask repair device of the present invention will be described with reference to the drawings. As a first embodiment of the present invention in FIG. 1, a basic configuration of an imaging optical system in which a mask having an OPC pattern is installed instead of the variable slit mechanism unit 20 in the general laser repair optical system shown in FIG. The figure is shown. The structure is such that the OPC glass mask 1 is illuminated by the collimated illumination light 7 and the pattern transmission image on the slit surface 10 is relay lenses 2 and 2.
The folding mirror 3 and the folding mirror 4 guide the light to the objective lens 5 and reduce the pattern transmission image on the image plane 6. The objective lens 5 has an autofocus mechanism (AF mechanism 9), and the OPC glass mask is
It is mounted on the fine movement positioning mechanism 8. OPC here
The pattern used is such that the image formation pattern is a square. The slit used in the conventional laser mask repair apparatus is not a slit having a fixed shape, but has a configuration in which each of the X and Y axes can control the slit width to a width of about 0 to 10 μm. On the other hand,
In the configuration of the present embodiment, the OPC mask 1 has a pattern of Cr thin film formed on a glass substrate like a normal photomask. Since the pattern on the OPC mask is one fixed pattern, it cannot be corrected according to the size of the defect. That is, the size of the mask having the OPC pattern is set to the minimum processing size, and for defects larger than that, the XY stage on which the defect photomask on the image plane 6 is mounted or the fine movement stage mounted on the XY stage. Is moved to correct and process the entire defect with multiple shots.

In the case where the stage movement is extremely small, about 50 nm or less, there is a method of moving the OPC mask itself in a small amount. This is because the processing optical system of the latest laser repair is usually x1 / 100 to x1 / 20 as described above.
It has a reduction ratio of about zero. Therefore, when the OPC mask is moved to shift the image forming position, the OP is moved by an amount 100 to 200 times the distance actually to be moved on the defective mask.
Since the C mask will be moved, 10n on the mask
In the case of fine adjustment on the order of m, control is easy and advantageous for ensuring accuracy. For example, when it is desired to accurately shift the processing correction portion by 10 nm, the movement is 2 μm in the case of × 1/200. In this way, if the movement is on the order of micron, even if the positioning system using the standard linear scale is used, the positioning can be performed in the unit of 50 nm, so that there is no problem in control decomposition.

In the above description of the embodiments, the OPC mask is a binary mask formed of a Cr thin film similar to a normal photomask, but various phase shifts developed for the purpose of high resolution. A mask can be used. For example, a Levenson type phase shift mask or a halftone type phase shift mask can be used.

FIG. 2 shows the configuration of the second embodiment. In this embodiment, three OPC patterns having different shapes are used.
This is an example of writing on the glass mask 11. As shown in FIG. 3, the plurality of patterns used here have serifs of the same size as the OPC pattern shown in the first embodiment (b ₁ = b ₂ , c ₁ = c ₂ ). Although the resolution of the corner portion is increased by the same amount, patterns having different shapes only in the size (a) of the square pattern are arranged. Three OPC patterns can be selected according to the size of the defect to be repaired. Further, it has an index mechanism for positioning each OPC pattern and the fine movement positioning mechanism described in the first embodiment. Figure 2
In the figure, the two mechanisms are represented by the coarse / fine movement positioning mechanism 12.

FIG. 4 shows the configuration of the third embodiment. Figure 4
Since the optical path from the relay lens 2 in FIG. 1 to the two folding mirrors, the objective lens 5, and the image forming surface 6 has the same configuration as in FIG. 1, these are omitted and the arrow “To image forming lens” is used. On behalf of. In the present embodiment, the variable XY slit 20 used in the conventional laser repair (FIG. 18) and the OPC of the second embodiment (FIG. 2) of the present invention are used.
Both the glass masks 11 (types having a plurality of OPC patterns) are mounted, the optical path of the collimated irradiation light is switched according to the shape and size of the defect to be corrected, and the slit 20 or the OPC glass mask 11 is selected as the irradiation target. It has a structure. Optical paths are switched by simultaneously inserting and retracting the two folding mirrors 22-1 and 22-2 in FIG. 4 in opposite directions.

When the variable XY slit 20 is selected in FIG. 5, and when the OPC glass mask 11 is selected in FIG.
The arrangement | positioning of a movable folding mirror and the optical path set by it are shown. When OPC mask is selected, 3 types of O
An example in which a PC pattern can be selected is shown. This mechanism includes a coarse / fine movement positioning mechanism 12 similar to that of the second embodiment.

In the present embodiment, the total optical path length from the light source to the image formation point does not differ due to the beam switching, but the variable XY slit 20 and the OPC glass mask 11 are different from each other as shown in the schematic diagram of FIG. When they are arranged right next to each other, the distance to the objective lens is different between the slit and the OPC mask. When this distance changes, the image forming position changes, so that either one of the focal points is deviated. Even if the objective lens is adjusted and focused, the magnification is changed, which is a problem. That is, in the present embodiment, it is important to arrange so that the distance to the lens does not change due to the switching of the optical path.
In reality, this adjustment is very severe. For example, an imaging processing optical system using an objective lens with NA = 0.85 requires AF (autofocus) accuracy of about 0.1 micron. Considering an image forming optical system of × 1/200, the alignment accuracy of the slit (OPC mask) in the optical axis direction is 20 μm. With this accuracy, it is required to adjust the slit position and the OPC mask position in each optical path. Therefore, in this embodiment, O
Fine movement positioning mechanism 2 in the optical axis direction on the mechanism part on the PC mask side
3 is provided.

Further, in this embodiment, the laser light for irradiating the variable XY slit 20 and the OPC glass mask 1 are used.
Although the case where the laser light for irradiating 1 is the same has been described, laser pulses having different peak values, pulse widths and pulse waveforms may be separately irradiated. For example, the OPC glass mask is irradiated with a pulse train of 100 fs to 300 ps, and the variable XY slit is irradiated with 10 ps to 500 p.
The effect can also be improved by irradiating a pulse train of s.

FIG. 7 shows a fourth embodiment. In this embodiment, unlike the beam expander shown in the third embodiment is common to the slit and the mask,
The variable XY slit 20 and the OPC glass mask 11 are provided with independent beam expanders 31 and 32, respectively. By making the beam expanders independent, it is possible to change the magnification of only one of the beam expanders, or to finely adjust the degree of collimation without changing the magnification. This makes it possible to further enhance the resolution effect.

FIG. 8 shows a fifth embodiment. In the present embodiment, the uniaxial slit width varying mechanism 40 is configured by using two OPC masks, that is, an OPC patterned glass mask 41 and an OPC patterned glass mask 42, in which the slit width can be varied only in the uniaxial direction. It is an example. FIG. 8 is a three-dimensional representation in which two glass masks are separated to show the positional relationship between the two OPC patterns.
(A) and FIG. 8 (B) which is a cutaway view in a horizontal plane passing through the center of the pattern. As shown in the sectional view of FIG. 8B, two glass masks having OPC patterns written therein are arranged with a minimum gap and the Cr pattern surfaces are inside each other. As mentioned earlier,
Considering the focus allowance at the processing point, the pattern gap is required to be about 20 microns or less. Actually, the interval is kept by sandwiching a resin sheet having a good sliding property of about 5 microns. A uniaxial slit width variable mechanism 40 is shown in FIG.
By substituting the OPC glass mask 1 of the laser repair optical system described above for fine adjustment of each glass mask in the left-right direction, only in the uniaxial direction,
Since the processing width can be changed freely, the correspondence at the time of correction is expanded.

FIG. 9 shows a sixth embodiment. Two uniaxial slit width varying mechanisms 40 using two OPC masks shown in FIG. 8, one uniaxial slit width varying mechanism 40-1 using an OPC mask pattern whose one is variable in width in the X direction,
The other is a uniaxial slit width variable mechanism 40-2 using an OPC mask pattern whose width is variable in the Y direction, and the optical path is switched by inserting / removing the folding mirror 22-1 and the folding mirror 22-2 to irradiate the image forming lens. The target that leads to
The configuration is such that one of the transmission images of the uniaxial slit width varying mechanism using the XY OPC mask pattern is selected. The present embodiment is an example in which a slit width adjusting mechanism using a similar OPC mask is provided for the other axis (orthogonal axis) that cannot be changed in the fifth embodiment (FIG. 8). In this embodiment, the movable folding mirror 2 is used.
The configuration is such that the optical path is switched by 2-1 and 22-2 to adjust the slit width in either direction to irradiate the image forming surface. Selection can be made according to the defect shape of the defect mask to be repaired.

FIG. 10 shows a seventh embodiment. In the present embodiment, the axes orthogonal to each other are obtained in the OPC mask adjusting mechanism by the optical path switching method in the sixth embodiment (FIG. 9), whereas the OPC mask adjusting mechanism has only one axis, but the rotating mechanism is used. By having it, the same effect can be obtained. The OPC glass mask 1 in the optical system shown in FIG. 1 or the OPC glass mask 11 in the optical system shown in FIG.

FIG. 11 shows an eighth embodiment. In this embodiment, the movable folding mirrors 22-1 and 22-2 in the optical system of the sixth embodiment of FIG. 9 are replaced with a fixed half mirror 51, and the optical axis of the collimated light is adopted. 8 is divided by a half mirror 51-1 into two parts.
The uniaxial slit width varying mechanism using the OPC mask pattern shown in the fifth embodiment is arranged so as to be orthogonal to each axis, and finally, the two beams are combined by the half mirror 51-2 (combining mirror), The configuration is such that the combined beam is imaged by an imaging lens. By using this embodiment, a convex shape, an L shape, a cross shape, or the like can be formed, so that a more complicated defect shape can be dealt with.

FIG. 12 shows a ninth embodiment. Also in the present embodiment, the optical axis of the collimated light is divided into two by the half mirror 51-1 and the glass mask 62 having a normal slit shape without OPC and the serif portion shape for OPC are independently provided. It has a configuration in which it is transmitted through the glass mask 61, these transmitted images are combined again by the half mirror 51-2, and the combined beam is imaged by an imaging lens. Ordinary slit shape without OPC,
Each serif shape has multiple patterns, select these,
It is configured so that the combination can be changed. By combining different serif sizes, it is possible to select a state in which the OPC effectiveness is different, and it is possible to further expand the width that can be accommodated, as in the previous embodiment.

FIG. 13 shows a tenth embodiment of the laser processing optical system. In the present embodiment, in the laser repair optical system using the OPC mask of the first embodiment shown in FIG. 1 of the present patent and the third embodiment shown in FIG. 4, the OPC mask is actually processed when the OPC mask is selected. It shows a specific example of an optical system for displaying the position to be accurately displayed. The structure includes an optical system of a laser beam for processing, an optical system for observing an OPC pattern, and an optical system for observing a processing point. The optical system of the laser beam for processing is such that the laser beam 25
Is placed and a dichroic mirror 71-2 (dual wavelength mirror) that transmits the illumination light 73 for observing the OPC pattern is placed, and the laser light 25 is reflected to reflect the OPC glass mask 11
Incident on. The laser transmission image of the OPC glass mask is transmitted through another dichroic mirror 71-1 having the same wavelength characteristic as 71-2, and is imaged via the relay lens 2-2, the folding mirror 21-1, and the objective lens 5. The image is formed on the surface 6. The optical system for observing the OPC pattern makes the illumination light 73 enter the dichroic mirror 71-2 from the direction orthogonal to the laser light 25, and
It is made incident on the C glass mask 11. The transmission image of the OPC glass mask is separated and transmitted using another dichroic mirror 71-1 to separate only the transmission image of the wavelength of the illumination light 73, and the folding mirror 21-2, the relay lens 2-1 and the folding mirror 21-3 are used. CCD of CCD camera 72-1 via
The configuration is such that an image is formed on the element. Further, the optical system for observing the processing point uses the image of the processing point on the image plane 6 as an objective lens 5, a folding mirror 21-1, a relay lens 2-2,
The light is transmitted through the dichroic mirror 71-1, and an image is formed on the CCD element of the CCD camera 72-2 via the folding mirror 21-4. With this configuration,
The shape of the OPC pattern can be accurately monitored, and it can be used for confirmation of the OPC mask position, confirmation of the OPC mask shape, and the like. If this information is converted into data using an image processing device, based on this data, the contour imaged by the OPC mask is displayed, and this contour is the actual machining shape obtained by the machining point observation optical system. It is very useful since it can be used as a pilot beam for indicating the processing area from the next time once it is adjusted to the image information indicating the position and the position.

FIG. 14 shows a system configuration diagram for displaying the processing position by using the processing optical system of the tenth embodiment. The personal computer (PC) shown in the figure
An image 84-1 obtained by directly monitoring the OPC pattern with the CCD camera 72-1 and the CCD camera 72-2
The images 84-2 obtained by observing the actual processing results are analyzed by the image processing device 81-1 and the image processing device 81-2, respectively, and the fine movement positioning of the stage 83-2 of the OPC mask is performed so that the data match. The mechanism is adjusted (calibrated) through the stage driver 82-2, or the XY stage 83-1 on which a defect correction mask to be processed is mounted is mounted on the stage driver 82.
It is possible to construct a system capable of displaying the machining position by controlling through -2.

FIG. 15 shows a schematic flow of processing position processing at this time.

[0026]

When the OPC mask shown in this patent is used, the laser repair apparatus is characterized in that it can be processed with a resolution higher than the resolution limit of the processing optical system used. Equivalently, since the optical design limit of the objective lens can be exceeded, there is an advantage that the present repair system can comply with the rule of one generation ahead. This method can also be supported by modifying the conventional slit mechanism. This is a very useful technique from the viewpoint of being able to significantly improve the level of the device at the minimum cost and in the shortest time. At present, when it is necessary to deal with the wiring rules that are progressing at a speed higher than that shown in the road map of semiconductors, the correspondence by this patent is valuable.

When a conventional laser repair system using a variable slit mechanism and an OPC mask is used as in the third embodiment of the present patent, a major defect is that the conventional slit mechanism is used and the slit width is around the minimum slit width. Defects are OPC
If the method of repairing with a mask is used, it is convenient because various defects that occur in the current photomask can be repaired at once.

In the modification of the halftone phase shift mask (HT-PSM), which has received the most attention in recent photomask technology, the effect of the present patent is even more remarkable.
This is because the HT mask such as MoSi absorbs the laser light relatively less than the ordinary Cr binary mask and is less susceptible to the thermal influence during processing.
In the image processing using the OPC mask for the mask, it can be expected that the corner portion has a radius of curvature of about half that in the case of the Cr mask. When processing MoSi, unless an OPC mask having a small serif is selected, the corners will be protruded, so it is necessary to select an optimum OPC shape. As described above, in the present patent, different serif shapes of OPC can be selected, so that the serif shape may be selected appropriately depending on the material of the mask to be modified. Furthermore, depending on the wavelength used by the laser repair device, it is also effective to manufacture the OPC mask itself by HT-PSM to realize further resolution UP at the image formation point.

Further, as described in the first embodiment,
In the case of processing using an OPC mask, movement accuracy for correction is required to be several tens of nm. In the conventional apparatus, the XY stage on which the defective mask to be processed is mounted is moved by a small amount by a piezo element or the like, but since feedback control cannot be performed, controllability is poor and accurate operation cannot be performed. If the fine movement mechanism of the OPC mask is controlled by attaching a linear scale, it is possible to easily perform an operation with an accuracy of several tens of nm on the processed surface. With this mechanism,
Automatic processing within a few 100 nm square is possible. Up until now, it was done manually, so it was often processed at uneven pitches, and the depth of engraving on the glass substrate was not uniform in most cases. It has the feature that it can be made flat.

Furthermore, the uniaxial O shown in the seventh embodiment is used.
A slit mask variable mechanism using a PC mask is prepared for two axes in orthogonal directions, and the two slits are simultaneously divided into two by half mirrors without switching the optical path. Then, these OPC mask mechanisms are respectively arranged and the half mirrors are used again. A convex shape, an L shape, and a cross shape can be formed by forming an image after combining them with each other. This is a shape that is useful for repairing defects in contact holes.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of an imaging optical system of a laser repair using an OPC pattern in a slit according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an image forming optical system of laser repair using a plurality of OPC patterns according to a second embodiment of the present invention.

FIG. 3 is a diagram showing details of OPC patterns having different shapes shown in FIG. 2;

FIG. 4 is a diagram showing a configuration of a variable XY slit width mechanism and an OPC mask switching unit according to a third embodiment of the present invention.

FIG. 5 is a diagram showing an optical path when a variable XY slit width mechanism in a third embodiment of the present invention is selected.

FIG. 6 is a diagram showing an optical path when an OPC mask according to a third embodiment of the present invention is selected.

FIG. 7 is a diagram showing a configuration when an independent beam expander is used for the variable XY slit width mechanism and the OPC mask according to the fourth embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of a uniaxial slit width varying mechanism using an OPC mask according to a fifth embodiment of the present invention.

FIG. 9 is a diagram showing a configuration in which a uniaxial slit width varying mechanism using an OPC mask according to a sixth embodiment of the present invention is used in both X and Y directions.

FIG. 10 is a diagram showing a configuration in which a rotating mechanism is combined with a uniaxial slit width varying mechanism using an OPC mask of a seventh embodiment of the present invention.

FIG. 11 is a diagram showing a configuration in which a uniaxial slit width varying mechanism using an OPC mask of an eighth embodiment of the present invention is used in both X and Y directions, and is further combined with a half mirror.

FIG. 12 is a diagram illustrating a serif portion of an OPC mask according to a ninth embodiment of the present invention, which is selected as an independent pattern and combined to form an OPC mask.
It is a figure which shows the structure which obtains a mask effect.

FIG. 13 is a diagram showing an optical system configuration capable of observing an OPC pattern according to a ninth embodiment of the present invention.

FIG. 14 is a diagram showing a configuration of a repair processing position display processing system according to a tenth embodiment of the present invention.

FIG. 15 is a diagram showing a flow of repair processing position display processing according to the tenth embodiment of the present invention.

FIG. 16 is a diagram showing an effect of improving a processed shape when image processing is performed with a normal slit and an OPC slit.

FIG. 17 is a diagram showing shapes of a design pattern and an OPC pattern.

FIG. 18 is a diagram showing a configuration of an image processing optical system used in a conventional typical laser repair.

FIG. 19 is a diagram showing parameters for OPC mask evaluation.

[Explanation of symbols]

1 OPC glass mask 2 relay lens 3 folding mirror 4 folding mirror 5 Objective lens 6 Image plane 7 Irradiation light 8 Fine movement positioning mechanism 10 slit surface 11 OPC glass mask 12 Coarse / fine movement positioning mechanism 20 variable XY slits 21 folding mirror 22 Folding mirror 25 laser light 31 beam expander 40 Uniaxial slit width variable mechanism 41 glass mask 42 glass mask 51 half mirror 61 glass mask 62 glass mask 71 dichroic mirror 72 CCD camera 73 Illumination light 81 Image processing device 82 Stage driver 83 stages 84 images

Claims (24)

[Claims] 1. A laser is irradiated with the laser emission light,
A slit mechanism capable of varying an arbitrary slit width in two dimensions, a glass mask having at least one pattern which irradiates the laser emission light and considers optical proximity effect correction (OPC) independent of the slit mechanism, The transmission image of the slit mechanism and an image forming optical system for forming a reduced image of the transmission image of the glass mask on the same plane, and the imaged light of the object to be processed arranged on the image forming surface. A laser repair device characterized by processing by points. 2. The laser according to claim 1, further comprising an optical path switching mechanism for selecting and irradiating the laser emission light with one of the slit mechanism of the variable slit width and the glass mask. Repair device. 3. The glass mask comprises a mechanism for moving in a direction perpendicular to an optical axis direction so that a pattern for irradiating the laser beam can be selected from the plurality of OPC patterns. The laser repair device according to claim 1. 4. The laser repair apparatus according to claim 1, wherein the OPC glass mask is made of a binary mask including a light transmitting area and a light shielding area, or a phase shift mask. 5. The laser mask repair apparatus according to claim 4, wherein the phase shift mask is one of a halftone type, a Levenson type, and a self-aligned type. 6. The laser repair apparatus according to claim 1 or 2, wherein the laser light for irradiating the slit mechanism and the glass mask have different pulse characteristics. 7. The laser light for irradiating the OPC mask is a pulse train having a pulse width of 100 fs to 300 ps, and the laser light for irradiating the slit mechanism is a pulse train having a pulse width of 10 ps to 500 ps. The laser repair device according to claim 6. 8. The laser repair apparatus according to claim 6, wherein the laser light having different pulse characteristics is laser light emitted from two different lasers. 9. The laser repair apparatus according to claim 1, wherein the OPC pattern used in the glass mask is a serif type or a hammerhead type. 10. The shifter material of the phase shift mask is MoSi-based, Si-based, ZrSi-based, Cr-based, Ti.
5. The laser repair apparatus according to claim 4, wherein any one of Si-based materials and materials based on these is used. 11. A square pattern of an OPC pattern, which is a laser, an optical branching unit that splits the laser beam into two beams, and generates a first split beam and a second split beam, and irradiates the first split beam. A first glass mask having only a portion, a second glass mask having only the serif portion of the OPC pattern positioned at the corner of the square pattern, which is irradiated with the second branched light, and the two glass masks. An optical merging means for synthesizing the transmission images, and an image forming optical system for reducing and forming the synthesized transmission images on the same plane are provided, and the object to be processed arranged on the image forming surface is synthesized as described above. A laser repair device, characterized by being processed by a light spot imaged on an OPC pattern. 12. The first and second glass masks,
2. The method according to claim 1, wherein the plurality of patterns each having a different shape or size are provided, and the pattern for irradiating the laser beam can be selected from the plurality of patterns.
1. The laser repair device according to 1. 13. A first device provided on the first glass mask.
When the length of one side of the square pattern is 100, one side of the second square of the serif portion of the second glass mask is 20 to 40, and the first square and the second square. 12. The laser repair apparatus according to claim 11, wherein a square processing is performed by the light spot imaged on the OPC pattern having a length of the overlapping portion of 0 to 20. 14. A beam expander capable of independently adjusting a beam divergence angle in an optical path between the optical path switching mechanism and the slit mechanism with variable slit width, and in an optical path between the optical path switching mechanism and the glass mask. The laser repair apparatus according to claim 1, further comprising: 15. The independent beam expander
15. The laser repair apparatus according to claim 14, wherein the expansion ratio different from that of the variable XY slit mechanism can be selected so that the processed shape when using the OPC mask is the best. 16. The glass mask comprises a fine adjustment mechanism having a resolution of M / 10 micron or less in the optical axis direction and 1 in the direction perpendicular to the optical axis, when the reduced image forming magnification is 1 / M.
15. The laser repair apparatus according to claim 1, further comprising a fine movement stage mechanism having a resolution of 0 M nanometer or less. 17. The laser repair apparatus according to claim 16, wherein the image processing position can be shifted by a minute amount by moving the glass mask in an axial direction perpendicular to the optical axis direction. 18. The laser repair device further comprises means for measuring the imaged light spot, and the fine movement stage mechanism constitutes a feedback servo system together with the imaged light spot measuring means, and the servo The laser repair apparatus according to claim 16, wherein the position of the image forming point in the optical axis direction is automatically controlled by a system. 19. The laser according to claim 16, wherein the focus position when processing with the variable XY slit mechanism and the focus position when processing with the OPC glass mask are completely matched. Repair device. 20. An OPC mask comprising a rectangular pattern and a pattern having serifs at the corners of the rectangular pattern in consideration of optical proximity correction, wherein the OPC pattern is composed of two masks. An OPC mask, wherein the rectangular pattern width can be varied in a uniaxial direction by sliding the masks in a uniaxial direction along a main surface. 21. A first OP according to claim 20, wherein the rectangular pattern width can be varied in the X-axis direction of the XY biaxial directions by irradiating a laser and the laser emission light.
21. A C mask and the second OPC mask according to claim 20, which is capable of varying the rectangular pattern width in the Y-axis direction by irradiating the laser emission light, and a transmission image of the first OPC mask. An image forming optical system for forming a reduced image of the transmission image of the second OPC mask on the same plane, and an object to be processed arranged on the image forming surface is processed by the imaged light spot. A laser repair device characterized by the above. 22. The laser light emitted from the first OP
22. The laser repair apparatus according to claim 21, further comprising a mechanism for switching an optical path for selecting and irradiating either the C mask or the second OPC mask. 23. A laser, a light splitting means for splitting the laser light into two beams to generate a first split light beam and a second split light beam, and irradiating the first split light beam and irradiating the X-axis of XY two axes The first OPC mask according to claim 20, wherein the rectangular pattern width can be varied in the axial direction, and the second branched light is irradiated to vary the rectangular pattern width in the Y-axis direction. 21. The second OPC mask according to claim 20, which is capable of performing the above, an optical combining means for synthesizing the transmission images of the two glass masks, and an imaging optical system for reducing the synthesized transmission images to form an image on the same plane. A laser repairing device, characterized in that the object to be processed disposed on the image forming surface is combined and processed by the light spot imaged on the OPC pattern. 24. A laser and a mechanism capable of irradiating the laser emission light to change the rectangular pattern width in the X-axis direction of the XY2 axes and rotating by 90 degrees in the Y-axis direction. 21. An OPC mask according to item 20, and an image forming optical system for forming a reduced image of a transmission image of the OPC mask, and an object to be processed arranged on the image forming surface is processed by the imaged light spot. A laser repair device characterized by the above.